GitLab

- now also track if the cellSet or cellZone has changed on point
  motion.

- handle tmp fields in interpolate methods

- special method interpolateInternal() for creating a volume field
  with zero-gradient treatment for patches from an internal field.

  This method was previously also called interpolate(), but that
  masked the ability to subset the internal field only.

  Ensight output needs the volume field:
      uses interpolateInternal().

  VTK output has separate handling of internal and patch fields:
      uses interpolate().

ENH: added fvMeshSubset mesh() method for baseMesh or subMesh.

- simplies coding when the fvMeshSubset may or may not be in active use.

ENH: update foamToEnsight to use newer methods in wrapped form

- static interpolate functions with renaming for manual use with
  fvMeshSubset (when fvMeshSubsetProxy may be too limiting in
  functionality)

- what was previously termed 'setLargeCellSubset()' is now simply
  'setCellSubset()' and supports memory efficient interfaces.

  The new parameter ordering avoids ambiguities caused by default
  parameters.

  Old parameter order:

      setLargeCellSubset
      (
          const labelList& region,
          const label currentRegion,
          const label patchID = -1,
          const bool syncCouples = true
      );

  New parameter order:

      setCellSubset
      (
          const label regioni,
          const labelUList& regions,
          const label patchID = -1,
          const bool syncCouples = true
      );

   And without ambiguity:

      setCellSubset
      (
          const labelUList& selectedCells,
          const label patchID = -1,
          const bool syncCouples = true
      );

- support bitSet directly for specifying the selectedCells for
  memory efficiency and ease of use.

- Additional constructors to perform setCellSubset() immediately,
  which simplifies coding.

  For example,

      meshParts.set
      (
          zonei,
          new fvMeshSubset(mesh, selectedCells)
      );

  Or even

      return autoPtr<fvMeshSubset>::New(mesh, selectedCells);

- reuse for foamToTecplot360 and foamToVTK.
- remove dependency on vtkMesh where possible.